Cement and other dry, powdered, bulk materials are transported by various means today. For example, often the powdered material is bagged, palletized, and transported in containers on barges. Great expense is incurred in the steps of bagging, placing the bags on pallets, and transporting the pallets because of the relatively small lots of bulk material involved. To overcome this problem, hoppers have been used instead of bags. Both methods are inefficient in utilizing the available storage space within a barge. Therefore, there has been interest in developing barge unloading systems where powdered bulk material is stored in large hoppers built into the hull and is automatically unloaded at the port of entry.
The Fuller-Kinyon "Airslide" barge unloading system ("Airslide" is a registered trademark of Fuller-Kinyon Company) is one such system for unloading cement and other bulk powdered material. As described in Fuller-Kinyon brochure FK-26-D, the unloading system includes a barge having fore and aft holds for the bulk powdered material. "Airslide" pneumatic conveyors are disposed in the bottom of each hold to convey the material to an impeller pump and rotary compressor at the center of the barge, where a plug of the bulk material is pushed into a high-pressure line that conveys the material to onshore storage facilities. The Fuller-Kinyon system is power and capacity inefficient. The impeller pump must be placed below the hold to unload the bulk material and, therefore, wastes some potential storage capacity of the barge.
An alternative pneumatic, self-unloading barge system is disclosed at page 22 of the Halliburton Company brochure entitled "Pneumatic Conveying Systems," SP-11078.
Various components for pneumatic conveying are known. For example, R. Perry and C. Chilton discuss pneumatic conveyors at pages 7-16 through 7-19 of the Chemical Engineers' Handbook, Fifth Edition. Halliburton sells "Air Trough" pneumatic fluidizer conveyors ("Air Trough" is a registered trademark of the Halliburton Company). Fuller-Kinyon sells "Airslide" gravity pneumatic conveyors ("Airslide" is a registered trademark of Fuller-Kinyon Company). AirKonvey Company sells vaccuum-pressure pneumatic conveyors, such as the "VACK II" conveyor ("VACK II" is a trademark of Premier Pneumatics, Inc.). Other vacuum-pressure pneumatic conveyors are disclosed in U.S. Pat. Nos. 4,168,864; 3,861,830; and 3,372,958 (incorporated by reference).